GPT, or GUID Partition Table, is a disk-partitioning scheme used by modern systems, especially those booting with UEFI. It defines how a drive is divided into partitions and stores metadata about each partition, including size, type, and a unique identifier. GPT replaced the older MBR layout on many machines because it supports larger disks and more partitions.
In cyber security, GPT matters because it shapes the boot chain and the placement of critical startup data such as the EFI System Partition. Attackers who tamper with partition tables can disrupt booting, hide malicious code, or interfere with recovery tools. Defenders check GPT when investigating unbootable systems, failed updates, or suspicious boot behavior. A valid GPT layout helps ensure firmware and operating-system components load from the expected locations and that security controls can verify disk structure during incident response.